Magic Item Quirks and Power  
                                                        by  The Elder Wyrm

For: All editions

I use a different spin on standard magic items in my world. I use what I call the Quirks/Powers Adjustment. The thinking behind this is that while there are some standard magical items, magic is an inexact science. For example, Schmendrik is commissioned to create a +3 battleaxe. He commissions the creation of the new battleaxe, takes it home and begins enchanting. During the time that he is enchanting it he is required to cast Negative Plane Protection spell. The battleaxe absorbs some of this power unbeknownst to the wizard or the warrior who commissioned the battleaxe. Several years go by, the warrior dies, all info about the battleaxe is lost, etc.
Enter our intrepid heroes who happen to stumble upon the battlefield where said warrior died. He is still gripping the weapon. They pry the axe from the warrior’s cold, dead, skeletal fingers. A new warrior begins using it and discovers during a battle with a wraith that the axe is uncannily good against undead. In a normal system, the warrior had found a standard +3 Battleaxe, under the Quirks/Powers system he may have found a +3 Battle Axe/+5 vs. undead.
The following table can help you determine whether or not an item has any quirks/powers:

d100 Result:

01-03 Major Quirk
04-10 Minor Quirk
11-89 Standard Listing
90-97 Minor Power
98-00 Major Power

Major quirks are along the lines of major functional problems:
Wands of Wonder that really make you wonder.
Potions of Super-healing that only heal bludgeoning damage.
Plate mail that is completely vulnerable to piercing weapons (effective AC 10 vs. P weapons).

Minor Quirks only place minor limits on the functionality of the item:
One in 10 times the item won't work (works best with charged items).
Magical weapons have pluses reduced vs. certain creature types or alignments.
Scrolls that can only be read by the light of a full moon or the dawning sun.

Minor powers would be minor boosts to the item:
An additional +1 or +2 vs. certain creatures.
In certain circumstance effectiveness increased by 10-20%.
A magical staff that eliminates the need for material components for fire based spells, etc.

Major Powers may lead to rewrites of entire items.
A quiver of Ehlonna that produces arrows with various effects.
A deck of many things with 12 extra never before seen cards.
A battle axe +3 that is actually a paladin’s Holy Weapon.

This system has worked well for my group. It keeps the characters off balance and they are always probing new items to see what their power limit is. The best one so far was a Robe of Useful Items full of sandwiches, peace treaties, fireworks, and whoopee cushions.